The present invention relates to an opening and closing mechanism provided on a device such as a printer utilizing a continuous-form sheet capable of causing a pair of sheet dust brushes, between which the continuous-form sheet is fed, for cleaning sheet dust on the continuous-form sheet, to be brought out of contact from each other.
An image forming apparatus, employing an electrophotographic type printer which prints information on the continuous-form printing sheet which is used for a conventional line printer has been known. In such an apparatus, an electrophotographic method, in which a photosensitive material on a photosensitive drum is exposed to light to form a latent image, a toner image being transferred on a recording sheet in accordance with the formed latent image, and the toner image being fixed by a fixing unit, is employed.
The continuous-form sheet is also called a fan-folded sheet and is folded sheets with feed holes, and hereinafter will be referred to as the fan-folded sheet. The folded portion is perforated so that it can be easily cut.
In this type of electrophotographic printer using the fan-folded sheet, generally an upper member is openably disposed on the main unit, the fan-folded sheet passing therebetween. By opening the upper member, the fan-folded sheet can be set in the printer.
Occasionally, on a surface of the fan-folded sheet, sheet dust, which occurs when the feed holes and perforations are made, may be present. The sheet dust tends to stay at the charger of the transfer section or at the photosensitive drum thereby causing trouble, for example, preventing a transfer operation. To prevent such trouble from occurring, a pair of cylindrical brushes are oppositely disposed in parallel at upper and lower portions of the sheet path. Accordingly, the fan-folded sheet is fed between the pair of sheet dust brushes, on a sheet entrance side, which is closer than the transfer section. By rotating the brushes in the direction opposed to the feed direction of the fan-folded sheet, the sheet dust is removed by the brushes.
However, as described above, since the pair of sheet dust brushes are arranged to be rotated, it is desirable that the brushes be in contact with each other, and both brushes are arranged to be provided on the main unit. Accordingly, when the fan-folded sheet is set, it should be passed between the sheet dust brushes, thereby requiring a very complicated operation. In addition, when the fan-folded sheet is jammed, it is very difficult to remove it.